//! The main module and entrypoint
//!
//! The operating system and app also starts in this module. Kernel code starts
//! executing from `entry.asm`, after which [`rust_main()`] is called to
//! initialize various pieces of functionality [`clear_bss()`]. (See its source code for
//! details.)
//!
//! We then call [`println!`] to display `Hello, world!`.
#![deny(missing_docs)]
#![deny(warnings)]
#![no_std]
#![no_main]
#![feature(panic_info_message)]
#![allow(unused)]

use core::arch::global_asm;

#[macro_use]
mod console;
mod lang_items;
mod sbi;

#[cfg(feature = "board_qemu")]
#[path = "boards/qemu.rs"]
mod board;

global_asm!(include_str!("entry.asm"));

/// clear BSS segment
pub fn clear_bss() {
    extern "C" {
        fn sbss();
        fn ebss();
    }
    (sbss as usize..ebss as usize).for_each(|a| unsafe {
        (a as *mut u8).write_volatile(0)
    });
}

/// the rust entry-point of os
#[no_mangle]
pub fn rust_main()-> ! {
    clear_bss();
    println!("zhuguoyin");

    extern "C" {
        fn stext();
        fn etext();
        fn srodata();
        fn erodata();
        fn sdata();
        fn edata();
        fn sbss();
        fn ebss();
        fn boot_stack();
        fn boot_stack_top();
    }

    println!(".text [{:#x}, {:#x}]", stext as usize, etext as usize);
    println!(".rodata [{:#x}, {:#x}]", srodata as usize, erodata as usize);
    println!(".data [{:#x}, {:#x}]", sdata as usize, edata as usize);
    println!("boot_stack [{:#x}, {:#x}]", boot_stack as usize, boot_stack_top as usize);
    println!(".bss [{:#x}, {:#X}]", sbss as usize, ebss as usize);

    #[cfg(feature = "board_qemu")]
    use crate::board::QEMUExit;

    

    #[cfg(feature = "board_qemu")]
    crate::board::QEMU_EXIT_HANDLE.exit_success();
}
